1. Field of the Invention
The present invention relates generally to telecommunications systems and methods for positioning a mobile subscriber within a cellular network, and specifically to monitoring received positioning requests for a mobile subscriber.
2. Background and Objects of the Present Invention
Cellular telecommunications is one of the fastest growing and most demanding telecommunications applications. Today it represents a large and continuously increasing percentage of all new telephone subscriptions around the world. A standardization group, European Telecommunications Standards Institute (ETSI), was established in 1982 to formulate the specifications for the Global System for Mobile Communication (GSM) digital mobile cellular radio system.
With reference now to FIG. 1 of the drawings, there is illustrated a GSM Public Land Mobile Network (PLMN), such as cellular network 10, which in turn is composed of a plurality of areas 12, each with a Mobile Switching Center (MSC) 14 and an integrated Visitor Location Register (VLR) 16 therein. The MSC 14 provides a circuit switched connection of speech and signaling information between a Mobile Station (MS) 20 and the PLMN 10. The MSC/VLR areas 12, in turn, include a plurality of Location Areas (LA) 18, which are defined as that part of a given MSC/VLR area 12 in which the MS 20 may move freely without having to send update location information to the MSC 14 that controls the LA 18. Each LA 18 is divided into a number of cells 22. The MS 20 is the physical equipment, e.g., a car phone or other portable phone, used by mobile subscribers to communicate with the cellular network 10, each other, and users outside the subscribed network, both wireline and wireless.
The MSC 14 is in communication with at least one Base Station Controller (BSC) 23, which, in turn, is in contact with at least one Base Transceiver Station (BTS) 24. The BTS is the physical equipment, illustrated for simplicity as a radio tower, that provides radio coverage to the cell 22 for which it is responsible. It should be understood that the BSC 23 may be connected to several BTS""s 24, and may be implemented as a stand-alone node or integrated with the MSC 14. In either event, the BSC 23 and BTS 24 components, as a whole, are generally referred to as a Base Station System (BSS) 25.
With further reference to FIG. 1, the PLMN Service Area or cellular network 10 includes a Home Location Register (HLR) 26, which is a database maintaining all subscriber information, e.g., user profiles, current location information, International Mobile Subscriber Identity (IMSI) numbers, and other administrative information, for subscribers registered within that PLMN 10. The HLR 26 may be co-located with a given MSC 14, integrated with the MSC 14, or alternatively can service multiple MSCs 14, the latter of which is illustrated in FIG. 1.
Determining the geographical position of an MS 20 within a cellular network 10 has recently become important for a wide range of applications. For example, location services (LCS) may be used by transport and taxi companies to determine the location of their vehicles. In addition, for emergency calls, e.g., 911 calls, the exact location of the MS 20 may be extremely important to the outcome of the emergency situation. Furthermore, LCS can be used to determine the location of a stolen car, for the detection of home zone calls, which are charged at a lower rate, for the detection of hot spots for micro cells, or for the subscriber to determine, for example, the nearest gas station, restaurant, or hospital, e.g., xe2x80x9cWhere am Ixe2x80x9d service.
As can be seen in FIG. 2 of the drawings, upon a network positioning request, the MSC 14 obtains, from the serving BTS 24 and BSC 23, a Timing Advance (TA) value, which corresponds to the amount of time in advance that the MS 20 must send a message in order for the serving BTS 24 to receive it in the time slot allocated to that MS 20. The TA value, in turn, provides location information regarding the MS 20 location. This is due to the fact that when a message is sent from the MS 20 to the BTS 24, there is a propagation delay, which depends upon the distance between the MS 20 and the BTS 24. The TA values are expressed in bit periods, and can range from 0 to 63, with each bit period corresponding to approximately 550 meters between the MS 20 and the BTS 24.
This TA value is forwarded to a Serving Mobile Location Center (SMLC) 270 for use in assisting the calculation of the geographical location of the MS 20. It should be noted that the SMLC 270 can use a number of different positioning mechanisms, including, but not limited to, Time of Arrival (TOA), Enhanced Observed Time Difference (E-OTD) and Global Positioning System (GPS). After the SMLC 270 calculates the MS 20 location, this location can be sent to a Location Application (LA) 280 that requested the positioning. It should be noted that the requesting LA 280 could be located within the MS 20 itself, within the MSC 14 or could be an external node, such as an Intelligent Network (IN) node. If the LA 280 is not within the MS 20 or within the MSC 14, the location information is sent to the requesting LA 280 via the MSC 14 and a Gateway Mobile Location Center (GMLC) 290.
Existing technology can provide mobile subscribers with the ability to prevent LAs 280 from positioning them in order to protect their privacy. However, in some cases, it is necessary for the specific LA 280 to position the MS 20 regardless of the privacy settings of the particular subscriber. For example, when the LA 280 is an emergency center or a law enforcement agency, the community interest in positioning the MS 20 outweighs the subscriber""s need for privacy. In this case, the privacy settings of the subscriber will need to be overridden in order for the emergency center or law enforcement agency to position the MS 20. in addition, LAs 280 may need to have the ability to override other location settings established by the subscriber. Thus, a Privacy Override Indicator (POI) (not shown) can be provided by network operators to allow an LA 280 to override the subscriber""s privacy settings in order to obtain the location of the mobile subscriber.
The POI is typically assigned on an individual LA 280 basis by a Gateway Mobile Location Center (GMLC) (not shown) during the registration of the LA 280 at the GMLC associated with the PLMN 10 that the LA 280 is located in. Normally, commercial-type LA""s 280 are not allowed to override the subscriber""s privacy settings, e.g., the assigned value of the POI is xe2x80x9cnot override.xe2x80x9d However, certain specific LA""s 280, such as law enforcement or E-911, which must be capable of positioning a subscriber regardless of the subscriber""s privacy settings, can be assigned a POI with the value xe2x80x9callowed to override subscriber""s privacy settings.xe2x80x9d It should be noted that when the subscriber is roaming, law enforcement LA""s 280 will need, in addition to the POI with the value xe2x80x9callowed to override subscriber""s privacy settings,xe2x80x9d a court order in order to be able to override the mobile subscriber""s privacy settings.
Furthermore, even though a mobile subscriber has established privacy settings, the mobile subscriber may want to allow certain other subscribers or LAs 280 to have the ability to position the mobile subscriber regardless of the mobile subscriber""s privacy settings. Such other subscribers could be, for example, the mobile subscriber""s family or member(s) of a particular group, such as, e.g., in the case where the subscriber is an employee of a taxi company, the operations center or the mobile subscriber""s manager. For those cases, the mobile subscriber may also want to put limits on the ability of those other subscribers or LA""s 280 to position him or her. For example, the mobile subscriber may only want to allow certain LA""s 280 to be able to position the mobile subscriber during certain hours or minutes of the day, certain days of the week or certain days, weeks or months of the year. In addition, the mobile subscriber may want to limit the number of allowable repetitive positionings by a particular subscriber or LA 280 per hour, day, week or year.
Therefore, each mobile subscriber can define a Subscriber Location Privacy Profile (SLPP) (not shown), which contains a list of preferred subscribers or LA""s 280 that have permission to position the mobile subscriber. The SLPP can also define the conditions under which each of the preferred LA""s 280 can position the mobile subscriber. For example, the mobile subscriber can limit the positioning by a particular preferred LA 280 to only certain hours of the day, certain days of the week and/or certain weeks of the year, and can limit the number of times that particular preferred LA 280 can request positioning of the mobile subscriber during those allowed times. The SLPP can preferably be connected to the mobile subscriber""s main subscription record in the HLR 26 and can be downloaded to the VLR 16 together the rest of the subscription information when the MS 20 is within the MSC/VLR area 12 (shown in FIG. 1).
By allowing a mobile subscriber to preserve his or her privacy, an LA 280 may fail in it""s attempt to position the mobile subscriber due to a restriction within the mobile subscribers SLPP. However, there is currently no mechanism for providing the identities of these failed requesting LA""s 280 to a mobile subscriber. This type of identity information may be beneficial to a mobile subscriber who has been threatened or who has requested certain individuals to not position him or her. Furthermore, LA 280 identity information might be useful to law enforcement agencies conducting an investigation of a missing person, stolen vehicle or stolen property or other type of crime against the mobile subscriber. For example, if a mobile subscriber was positioned by an LA 280, and that mobile subscriber is reported as missing, a law enforcement agency can determine the identity of the requesting LA 280, and subpoena that LA""s 280 records to determine the last known location of the missing mobile subscriber. Furthermore, in some cases, the LA 280 identity information may be useful to law enforcement agencies in tracking down criminals who try to position their victims.
Even if an LA 280 is successful in positioning an MS 20, the mobile subscriber is not provided with LA 280 identity information during or after the positioning. Many mobile subscriber""s may be curious about who is positioning them. In sum, regardless of whether a positioning request is successful or unsuccessful, the mobile subscriber does not have any knowledge of the identity of the requesting LA 280.
It is, therefore, an object of the present invention to monitor all successful and unsuccessful attempts by a third party to locate a mobile subscriber and to provide identity information concerning that third party to the mobile subscriber.
It is a further object of the present invention to send Location Application identity information directly to a mobile station that was positioned successfully or unsuccessfully.
It is still a further object of the present invention to include Location Application identity information concerning Location Applicant""s that attempt to position a mobile subscriber on that mobile subscriber""s monthly bill.
It is still a further object of the present invention to maintain a positioning subscriber record including a list of the identities of all requesting Location Applications for a mobile subscriber.
The present invention is directed to telecommunications systems and methods for monitoring all successful and unsuccessful attempts by third parties to locate a mobile subscriber and providing identity information associated with those third parties to the mobile subscriber. Whenever a positioning request is received by a Gateway Mobile Location Center (GMLC), the GMLC, before returning a response to the requester, e.g., either location information or a rejection message, maintains a record of all information related to the positioning request, including the identity of the requester. The GMLC can download this positioning record to the mobile subscriber""s Home Location Register (HLR), which can append at least identity information regarding the requester, and preferably, a time stamp, to the mobile subscriber""s permanent record in the HLR. The identity information can be provided directly to the mobile subscriber on the Mobile Station (MS) associated with the mobile subscriber and/or included in the mobile subscriber""s monthly bill.